Fragmentation Experiment and Model for Falling Mercury Drops

The experiment consists of counting and measuring the size of the many fragments observed after the fall of a mercury drop on the floor. The size distribution follows a power-law for large enough fragments. We address the question of a possible crossover to a second, different power-law for small enough fragments. Two series of experiments were performed. The first uses a traditional film photographic camera, and the picture is later treated on a computer in order to count the fragments and classify them according to their sizes. The second uses a modern digital camera. The first approach has the advantage of a better resolution for small fragment sizes. The second, although with a poorer size resolution, is more reliable concerning the counting of all fragments up to its resolution limit. Both together clearly indicate the real existence of the quoted crossover. The model treats the system microscopically during the tiny time interval when the initial drop collides with the floor. The drop is modelled by a connected cluster of Ising spins pointing up (mercury) surrounded by Ising spins pointing down (air). The Ising coupling which tends to keep the spins segregated represents the surface tension. Initially the cluster carries an extra energy equally shared among all its spins, corresponding to the coherent kinetic energy due to the fall. Each spin which touches the floor loses its extra energy transformed into a thermal, incoherent energy represented by a temperature used then to follow the dynamics through Monte Carlo simulations. Whenever a small piece becomes disconnected from the big cluster, it is considered a fragment, and counted. The results also indicate the existence of the quoted crossover in the fragment-size distribution.Comment: 6 pages, 3 figure

Mitochondrial Oxidative Stress and Calcium-Dependent Permeability Transition are Key Players in the Mechanisms of Statins-Associated Side Effects

Statins are cholesterol-lowering medicines utilized worldwide and are associated with reduced risk of cardiovascular mortality and events. However, 0.5–10% of patients suffer from adverse effects especially on skeletal muscle. Recently, new onset of diabetes has been reported in subjects on statin therapy. Pro- and anti-oxidant effects of statins have been reported, thus fostering a debate. Previously reported data provide evidence that statins induce alterations in intracellular calcium homeostasis and mitochondrial dysfunctions that can be counteracted by antioxidants (e.g., CoQ10, creatine, and L-carnitine). Therefore, we have proposed that statin-induced inhibition of mitochondrial respiration leads to oxidative stress that opens a calcium-dependent permeability transition pore, an event that may lead to cell death. In addition, mitochondrial oxidative stress caused by statin treatment may be a signal for cellular antioxidant system responses such as catalase upregulation, possibly explaining the alleged statins’ antioxidant properties. Muscle mitochondrial dysfunction induced by statin treatment may be associated with the peripheral insulin resistance and may explain statins-induced new onset of diabetes. Together, the data presented in this review suggest that the statins’ detrimental effects can be prevented by co-administration of antioxidants

Cinco anos do PPGED-UEPA na Amazônia: trajetórias, avanços e possibilidades acadêmicas

Este artigo socializa a trajetória vivenciada pelo"Programa de Pós-Graduação em educação-Mestrado, do Centro de Ciências Sociais e Educação (CCSE), da Universidade do Estado do Pará"(UEPA), em seus cinco anos de existência. Apresenta os avanços e dificuldades apresentadas no"percurso de consolidação de seu projeto acadêmico, com base em levantamento bibliográfico e"documental. Com setenta dissertações defendidas"em duas linhas de pesquisa o PPGED tem contribuído para fortalecer a produção educacional em"contextos amazônicos. Mesmo com os avanços"significativos visualizados tanto na infraestrutura"como nos encaminhamentos didático-científicos,"o Programa sente falta de políticas institucionais"que garantam sua autonomia de gestão, o que inclui a destinação de orçamento necessário para"manter as suas ações. Neste aspecto, há necessidade de se manter diálogo permanente entre"o PPGED e as instâncias a que o programa está"vinculado, de modo a garantir condições para"produção do conhecimento e assim fortalecer o"campo educacional, especialmente na Amazônia Paraense."Palavras-chave: Educação. Programa de Pós- graduação. UEPA. Amazônia."Five years of "PPGED -UEPA in the Amazon: routes, trajectories, improvements and academic possibilities"This article socializes the trajectory experienced by the Post-graduate Program in Education (PPGED)Master’s Degree of Centro de Ciências Sociais e Educação (CCSE), of Universidade do Estado do Pará (UEPA), along its five years of existence. It presents improvements and difficulties emerged throughout the consolidation of its academic project, based on bibliographic and documental research. The PPGED has registered seventy seven developed dissertations in its two research areas and has contributed to strengthen the educational production within Amazonian contexts. Despite the relevant and evident progress achieved both in infrastructure and in scientific and didactic processes, the Program still lacks institutional policies that guarantee its management autonomy, which includes the destination of the necessary budget in order to maintain its actions. Concerning this, it is necessary to maintain permanent dialogue between PPGED and the other instances to which the program is linked, aiming at developing conditions for the production of knowledge and thus strengthening the educational field, especially in the Amazon of Para.Keywords: Education. Post Graduate Program. UEPA. Amazon." ""

LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering

[EN] Li2O-SiO2-ZrO2 (LZS) glass-ceramics have high mechanical strength, hardness, resistance to abrasion and chemical attack, but also a high coefficient of thermal expansion (CTE), which can be reduced adding alumina nanoparticles. The conventional glass-ceramic production is relatively complex and energy consuming, since it requires the melting of the raw materials to form a glass frit and a two-step milling process to obtain particle sizes adequate for compaction. This study describes the preparation of LZS glass-ceramics through a colloidal processing approach from mixtures of SiO2 and ZrO2 nanopowders and a Li precursor (lithium acetate obtained by reaction of the carbonate with acetic acid). Concentrated suspensions were freeze-dried to obtain homogeneous mixtures of powders that were pressed (100 MPa) and sintered conventionally and by spark plasma sintering. The effect of the alumina nanoparticles additions on suspensions rheology, sintering behavior and properties such as thermal expansion, thermal conductivity, hardness and Young's modulus were evaluated. (C) 2017 Elsevier Ltd. All rights reserved.This work has been supported by Ministerio de Economia y Competitividad (MINECO) and FEDER Funds under grant No MAT2016-67586-C3-R. Authors greatly acknowledge the financial Support of CAPES in the frame of the International Cooperation Program Science without Borders for Special Visiting Researcher PVE (MEC/MCTI/CAPES/CNPQ/FAPs/No 71/2013), Project no. A011/2013. A. Borrell acknowledges the MINECO for her Juan de la Cierva-Incorporacion contract (IJCI-2014-19839).Arcaro, S.; Novaes De Oliveira, A.; Gutierrez-Gonzalez, C.; Salvador Moya, MD.; Borrell Tomás, MA.; Moreno, R. (2017). LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering. Journal of the European Ceramic Society. 37(16):5139-5148. https://doi.org/10.1016/j.jeurceramsoc.2017.03.023S51395148371

Cytotoxic Effects Of Zoledronic Acid On Human Epithelial Cells And Gingival Fibroblasts

Bisphosphonate-induced osteonecrosis has been related to the cytotoxicity of these drugs on oral mucosa cells. A previous study showed that 5 μM of zoledronic acid (ZA), a nitrogen-containing bisphosphonate, is the highest concentration of this drug found in the oral cavity of patients under treatment. Therefore, in order to simulate an osteonecrosis clinical condition, the aim of this study was to evaluate the highest concentration of ZA applied on human epithelial cells (HaCaT) and gingival fibroblasts. For this purpose, cells (3x104 cells/cm2) were seeded in wells for 48 h using complete culture medium (cDMEM). After 48 h incubation, the cDMEM was replaced by fresh serum-free culture medium (DMEM-FBS) in which the cells were maintained for additional 24 h. Then, 5 μM ZA were added to the DMEM-FBS and the cells incubated in contact with the drug for 48 h. After this period, the number of viable cells (trypan blue), cell viability (MTT assay), total protein (TP) production and cell morphology (SEM analysis) were assessed. Data were analyzed statistically by Mann-Whitney, ANOVA and Tukey's test (α=0.05). ZA caused a significant reduction in the number of viable cells and decreased the metabolic activity of both cell lines. However, decrease of TP production occurred only in the epithelial cell cultures. Morphological alterations were observed in both cell types treated with ZA. In conclusion, ZA (5 μM) was cytotoxic to human epithelial cells and gingival fibroblast cultures, which could be associated, clinically, with the development of bisphosphonateinduced osteonecrosis.246551558Civitelli, R., Napoli, N., Armamento-Villareal, R., Use of intravenous bisphosphonates in osteoporosis (2007) Curr Osteoporos Rep, 5, pp. 8-13Cohen, S.B., An update on bisphosphonates (2004) Curr Rheumatol Rep, 6, pp. 59-65Rogers, M.J., Watts, D.J., Russel, R.G., Overview of bisphosphonates (1997) Cancer, 80, pp. 1652-1660Rogers, M.J., Gordon, S., Benford, H.L., Coxon, F.P., Luckman, S.P., Monkkonen, J., Cellular and molecular mechanisms of action of bisphosphonates (2000) Cancer Supl, 88, pp. 2961-2978Lawson, M.A., Xia, Z., Barnett, B.L., Triffitt, J.T., Phipps, R.J., Dunford, J.E., Differences between bisphosphonates in binding affinities for hydroxyapatite (2010) J Biomed Mater Res Part B: Appl Biomater, 92, pp. 149-155Allen, M.R., Burr, D.B., The pathogenesis of bisphosphonate-related osteonecrosis of the jaw: So many hypotheses, so few data (2009) J Oral Maxillofac Surg, 67, pp. 61-70Otto, S., Pautke, C., Opelz, C., Wesphal, I., Drosse, I., Swager, J., Osteonecrosis of the jaw: Effects of bisphosphonate type, local concentration, and acidic milieu on the pathomechanism (2010) J Oral Maxillofac Surg, 68, pp. 2837-2845Reid, I.R., Booland, M.J., Is bisphosphonate-associated osteonecrosis of the jaw caused by soft tissue toxicity? (2007) Bone, 41, pp. 318-320Scheper, M.A., Badros, A., Chausparat, R., Cullen, K.J., Meiller, T.F., Effect of zoledronic acid on oral fibroblasts and epithelial cells: A potential mechanism of bisphosphonate-associated osteonecrosis (2009) Br J Haematol, 144, pp. 667-676Scheper, M.A., Badros, A., Salama, A.R., Wartburton, G., Cullen, K.J., Weikel, D.S., A novel bioassay model to determine clinically significant bisphosphonate levels (2009) Support Care Cancer, 17, pp. 1553-1557Ruggiero, S.L., Mehrotra, B., Rosenberg, T.J., Engroff, S.L., Osteonecrosis of the jaws associated with the use of bisphosphonates: A review of 63 cases (2004) J Oral Maxillofac Surg, 62, pp. 527-534Walter, C., Klein, M.O., Pabst, A., Al-Nawas, B., Duscher, H., Ziebart, T., Influence of bisphosphonates on endothelial cells, fibroblasts, and osteogenic cells (2010) Clin Oral Investig, 14, pp. 35-41Kumar, S.K.S., Gorur, A., Schaauddin, C., Shuler, C.F., Costerton, J.W., Sedghizadeh, P.P., The role of microbial biofilms in osteonecrosis of the jaw associated with bisphosphonate therapy (2010) Curr Osteoporos Rep, 8, pp. 40-48Aas, J.A., Paster, B.J., Stokes, L.N., Olsen, I., Dewhirst, F.E., Defining the normal bacterial flora of the oral cavity (2005) J Clin Microbiol, 43, pp. 5721-5732Basso, F.G., Pansani, T.N., Turrioni, A.P.S., Bagnato, V.S., Hebling, J., de Souza Costa, C.A., In vitro wound healing improvement by low-level laser therapy application in cultured gingival fibroblasts (2012) Int J Dent, , [Epub ahead of print. DOI: 10.1155/2012/719452]Wiegand, C., Hipler, U., Methods for the measurement of cell and tissue compatibility including tissue regeneration process (2008) GMS Krankenhhyg Interdiszip, 3, pp. 1863-5245Basso, F.G., Oliveira, C.F., Kurachi, C., Hebling, J., de Souza Costa, C.A., Biostimulatory effect of low-level laser therapy on keratinocytes in vitro (2013) Lasers Med Sci, 28, pp. 367-374De Souza Costa, C.A., Duarte, P.T., de Souza, P.P., Giro, E.M., Hebling, J., Cytotoxic effects and pulpal response caused by a mineral trioxide aggregate formulation and calcium hydroxide (2008) Am J Dent, 21, pp. 255-261Oliveira, C.F., Basso, F.G., Lins, E.C.C., Kurachi, C., Hebling, J., Bagnato, V.S., Increased viability of odontoblast-like cells subjected to low-level laser irradiation (2010) Laser Phys, 20, pp. 1659-1666Read, S.M., Northcote, D.H., Minimization of variation in the response to different proteins of the Coomassie blue G dye-binding assay for protein (1981) Anal Biochem, 116, pp. 53-64Oliveira, C.F., Basso, F.G., Lins, E.C., Kurachi, C., Hebling, J., Bagnato, V.S., In vitro effect of low-level laser on odontoblast-like cells (2011) Laser Phys Lett, 8, pp. 155-163Simon, M.J.K., Niehoff, P., Kimming, B., Wiltfang, J., Açil, Y., Expression profile and synthesis of different collagen types I, II III and V of human gingival fibroblasts, osteoblasts, ans SaOs-2 cells after bisphosphonate treatment (2010) Clin Oral Investig, 14, pp. 51-58Migliorati, C.A., Siegel, M.A., Elting, L.S., Bisphosphonate-associated osteonecrosis: A long-term complication of bisphosphonate treatment (2006) Lancet Oncol, 7, pp. 508-514Werner, S., Krieg, T., Smola, H., Keratinocyte-fibroblast interactions in wound healing (2007) J Investigative Dermatol, 127, pp. 998-1008Ravosa, M.J., Ning, J., Liu, Y., Stack, M.S., Bisphosphonate effects on the behavior of oral epithelial cells and oral fibroblasts (2011) Arch Oral Biol, 56, pp. 491-49

Editorial

Editoria

A quantum-like description of the planetary systems

The Titius-Bode law for planetary distances is reviewed. A model describing the basic features of this rule in the "quantum-like" language of a wave equation is proposed. Some considerations about the 't Hooft idea on the quantum behaviour of deterministic systems with dissipation are discussed.Comment: LaTex file, 17 pages, no figures. Version published in Foundations of Physics, August 200

In Vitro Effect Of Low-level Laser Therapy On Typical Oral Microbial Biofilms

The aim of this study was to evaluate the effect of specific parameters of low-level laser therapy (LLLT) on biofilms formed by Streptococcus mutans, Candida albicans or an association of both species. Single and dual-species biofilms - SSB and DSB - were exposed to laser doses of 5, 10 or 20 J/cm 2 from a near infrared InGaAsP diode laser prototype (LASERTable; 780 ± 3 nm, 0.04 W). After irradiation, the analysis of biobilm viability (MTT assay), biofilm growth (cfu/mL) and cell morphology (SEM) showed that LLLT reduced cell viability as well as the growth of biofilms. The response of S. mutans (SSB) to irradiation was similar for all laser doses and the biofilm growth was dose dependent. However, when associated with C. albicans (DSB), S. mutans was resistant to LLLT. For C. albicans, the association with S. mutans (DSB) caused a significant decrease in biofilm growth in a dose-dependent fashion. The morphology of the microorganisms in the SSB was not altered by LLLT, while the association of microbial species (DSB) promoted a reduction in the formation of C. albicans hyphae. LLLT had an inhibitory effect on the microorganisms, and this capacity can be altered according to the interactions between different microbial species.226502510Marques, M.M., Pereira, A.N., Fujihara, N.A., Nogueira, F.N., Eduardo, C.P., Effect of low-power laser irradiation on protein synthesis and ultrastructure of human gingival fibroblasts (2004) Lasers Surg Med, 34, pp. 260-265Damante, C.A., de Micheli, G., Miyagi, S.P.H., Feist, I.S., Marques, M.M., Effect of laser phototherapy on the release of fibroblast growth factors by human gingival fibroblasts (2009) Lasers Med Sci, 24, pp. 885-891Moritz, A., Schoop, U., Goharkhay, K., Schauer, P., Doertbudak, O., Wernisch, J., Treatment of periodontal pockets with a diode laser (1998) Lasers Surg Med, 22, pp. 302-311Nussbaum, E.L., Lilge, L., Mazzulli, T., Effects of 630-, 660-, 810-, and 905-nm laser irradiation delivering radiant exposure of 1-50 J/cm 2 on three species of bacteria in vitro (2002) J Clin Laser Med Surg, 20, pp. 325-333Nussbaum, E.L., Lilge, L., Mazzulli, T., Effects of low-level laser therapy (LLLT) of 810 nm upon in vitro growth of bacteria: Relevance of irradiance and radiant exposure (2003) J Clin Laser Med Surg, 21, pp. 283-290Lino, M.D.M.C., Carvalho, F.B., Oliveira, L.R., Magalhães, E.B., Pinheiro, A.L.B., Ramalho, L.M.P., Laser phototherapy as a treatment for radiotherapy-induced oral mucositis (2011) Braz Dent J, 22, pp. 162-165Maver-Biscanin, M., Mravak-Stipetic, M., Jerolimov, V., Biscanin, A., Fungicidal effect of diode laser irradiation in patients with denture stomatitis (2004) Lasers Surg Med, 35, pp. 259-262Dworkin, M., Endogenous photosensitization in a carotinoidless mutant of Rhodopseudomonas speroides (1958) J Gen Physiol, 43, pp. 1099-1112Rosenberg, B., Kemeny, G., Switzer, R.C., Hamilton, T.C., Quantitative evidence for protein denaturation as the cause of thermal death (1971) Nature, 232, pp. 471-473Krespi, Y.P., Kizhner, V., Nistico, L., Hall-Stoodley, L., Stoodley, P., Laser disruption and killing of methicillin-resistant Staphylococcus aureus biofilms (2011) Am J Otolaryngol, 32, pp. 198-202Shirtliff, M.E., Peters, B.M., Jabra-Rizk, M.A., Cross-kingdom interactions: Candida albicans and bacteria (2009) FEMS Microbiol Lett, 299, pp. 1-8Pereira-Cenci, T., Deng, D.M., Kraneveld, E.A., Manders, E.M.M., del Bel, C.A.A., ten Cate, J.M., The effect of Streptococcus mutans and Candida glabrata on Candida albicans biofilms formed on different surfaces (2008) Arch Oral Biol, 53, pp. 755-764Marsh, P.D., Microbial ecology of dental plaque and its significance in health and disease (1994) Adv Dent Res, 8, pp. 263-271Karkowska-Kuleta, J., Rapala-Kozik, M., Kozik, A., Fungi pathogenic to humans: Molecular bases of virulence of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus (2009) Acta Biochim Pol, 56, pp. 211-224Thein, Z.M., Samaranayake, Y.H., Samaranayake, L.P., Dietary sugars, serum and the biocide chlorhexidine digluconate modify the population and structural dynamics of mixed Candida albicans and Escherichia coli biofilms (2007) APMIS, 115, pp. 1241-1251Kwieciński, J., Eick, S., Wójcik, K., Effects of tea tre (Melaleuca alternifolia) oil on Staphylococcus aureus in biofilms and stationary phase (2009) Int J Antimicrob Agents, 33, pp. 343-347Wang, Z.C., Fan, L.Y., Jiang, J.Q., Cai, W., Ding, Y., Study on the counting of Streptococcus mutans, Streptococcus sanguis, Haemophilus actinomycetemcomitans by methyl thiazolyl tetrazolium colorimetric method (2010) Hua Xi Kou Qiang Yi Xue Za Zhi, 28, pp. 306-310Nguyen, P.T.M., Abranches, J., Phan, T., Marquis, R.E., Repressed respiration of oral Streptococci grow in biofilms (2002) Curr Microbiol, 44, pp. 262-266Singleton, S., Treloar, R., Warren, P., Watson, G.K., Hodgson, R., Allison, C., Methods for microscopic characterization of oral biofilms: Analysis of colonization, microstructure, and molecular transport phenomena (1997) Adv Dent Res, 11, pp. 133-149Jarosz, L.M., Deng, D.M., van der Mei, H.C., Crielaard, W., Krom, B.P., Streptococcus mutans competence-stimulating peptide inhibits Candida albicans hypha formation (2009) Eukaryot Cell, 8, pp. 1658-1664Dortbudak, O., Haas, R., Bernhart, T., Mailath-Pokorny, G., Lethal photosensitization for decontamination of implant surface in the treatment of peri-implantitis (2001) Clin Oral Implant Res, 12, pp. 104-10

Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems

A PL spherical harmonics-nodal collocation method is applied to the solution of the multidimensional neutron source transport equation. Vacuum boundary conditions are approximated by setting Marshak's conditions. The method is applied to several 1D, 2D and 3D problems with isotropic fixed source and with isotropic and anisotropic scattering. These problems are chosen to test this method in limit conditions, showing that in some cases a high order $P_L$ approximation is required to obtain accurate results and convergence. Results are also compared with the ones provided by several reference codes showing good agreement. It is also shown that Marshak's approximation to vacuum boundary conditions gives the same results that simulating vacuum with a purely absorbing medium and setting zero flux boundary conditions.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE2011-22823, and the Generalitat Valenciana under project PROMETEO11/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2016). Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems. Annals of Nuclear Energy. 87:89-100. https://doi.org/10.1016/j.anucene.2015.07.040S891008